This invention relates to high speed operating weighing/conveyor machines such as are used in the food and other commodity packaging/weighing/checkweighing industries or the like. Prior machines for such purposes are disclosed for example in U.S. Pat. Nos. 2,838,176; 3,070,214; 3,180,475; 3,955,665 and 4,114,707.
More particularly, the invention relates to so-called powered platform scales, such as are used in systems for weighing discrete articles being conveyed in succession at high speeds over a weighing device; the "net" weights of which in most cases are to be visually displayed and graphically recorded. Also, in some cases such measurements are used to control devices for rejection from the delivery line of underloaded or overloaded packages or containers, as is well known in the art. The weight detecting/reporting components of such prior machines are subjected to dynamic error inductive influences such as are not encountered by "stationary" platform type weighing machines.
Prior machines for such purposes have typically comprised vertically "stacked" structural assemblies, at the bases of which reside the load cell or other weight-measuring component which is surmounted by the article transport weighing conveyor which is driven by an externally based motor and drive system. Such assemblies are accordingly statically imbalanced and top-heavy and therefor inherently subject to magnification of typically encountered dynamic unbalancing forces which when transmitted to the article weight detecting mechanism result in inaccurate weight measurement reports. Also, such encounters may apply physically destructive forces upon the mechanism such as call for constant maintenance attention; shut-downs, and repair expenses.
Such unbalancing impulses may be introduced for example by environmental shop noises; conveyor belt flutterings; drive chain or belt chatter vibrations; vagarious placements on the conveyor of the items to be weighed, and the intermittent item on-loading/off loading effects on the conveyor such as tend to disrupt smooth running operations of the conveyor. In prior machines, such impulses develop into torque moment forces and on occasion acquire resonance, and operate through substantial leverages relative to weight-measuring mechanism; thereby interfering with accurate readings especially in the case of high speed operations.
The present invention features a unique system for mounting the masses of the loads-carrying conveyor mechanism thereof as well as its motor and power train components relative to the weight-measuring component(s) thereof. This enables the machine to operate at higher speeds (and therefore higher capacities) compared to machines previously available to the industry, while correctly reporting the net weights of items such as are fleetingly conveyed in succession thereover.